The futuristic metal idea that has been adopted by alot of people who have said how G1 would work in real life or in Live action, is based around the comics/cartoons. The concept of how the faces would work was not something that had any set rules, it was left down to the individual artist at the time. This is more evident in the comics, when artists who were more used to drawing human characters, gave the bots human like hands rather than mechanical looking hands, again with the faces. Anyone who can draw will tyell you hands are tricky to draw, and faces are too. Hnds and faces are important when telling a story as both can be used to convey emotion, tools which are very important when telling a story. Due to deadlines aand lack of experience maybe, most artists either did hands and faces in there tried and tested biological look, and if we were lucky the hands were made to look mechanical. Sometime sthe bots even had teeth and even saliva.
Mechanical faces have become a terade mark of the live action movie, but there roots stem back from G1. I think the old answer of alien technology and flexible metal is a cop out, as why aren'tother parts using this flexible metal. It's just an easy answer, for a problem that with some time and effort can be easily solved. A mechanical face doesn't have to be as obscure as the live action movie, and a full range of motion isn't always needed to convey alot of expression.
I think mechanical faces should be the norm through out the whole transformers series, from simplistic G1 to elaborate live action with ethe exception of animate detc. Eyes show plenty of emotion, and prime prove sthat with his faceplate covering most of his face. There are plenty of actors on TV with there face pumped full of botox more or less parallising there face and they are still acting, not very well mind you. But even if there is some compramise, which I don't think there would be, I realy feel flexible looking faces or just simple flowing cartoony lines should be left to the likes of animated and spin off lines like robot heroes and mighty muggs which are stylised version so it works there. Human hands just look wrong, I still see it used today especialy in some manga, and what's with teeth and saliva.
I know some of you are fond of this old nostalgic style, but things have moved with the way transformers are brought to life by artists, but he way G1 and many other lines, have had the issue of how there faces are tackled, is still not fully solved convincibly. Ithink we can all agree that the way the hands are rendered now look convincing, and it is rare that we see human hands on a robot. But Faces are still tackled in many different ways, and I have read alot of threads and no one seems to agree on one thing. Alot of people seem to think the mechanical look came around from the movie. The movie prooves that it works, but the original toys and some artists today have proven a simpler way can work for G1, it just has to be adopted across the board. Everyone has mixed vues on G1 on going with the movie based inspired look. I'm in 2 mindas about it, and although I think the faces look iffy, I still think if reworked they could look really good. But a more simpler mechanical look is already therew. Take a closer look at some of your toys, and newer lines also have slits and grooves indicating a tyraditional mechanical movement is involved rather than a more biological flexible method
